Rb. Zhao et al., FLIG AND FLIM DISTRIBUTION IN THE SALMONELLA-TYPHIMURIUM CELL AND FLAGELLAR BASAL BODIES, Journal of bacteriology, 178(1), 1996, pp. 258-265
Salmonella typhimurium FliG and FliM are two of three proteins known t
o he necessary for flagellar morphogenesis as well as energization and
switching of flagellar rotation, We have determined FliC and FliM lev
els in cellular fractions and in extended flagellar basal bodies, usin
g antibodies raised against the purified proteins. Both proteins were
found predominantly in the detergent-solubilized particulate fraction
containing flagellar structures, Basal flagellar fragments could be se
parated from partially constructed basal bodies by gel filtration chro
matography. FliG and FliM were present in an approximately equimolar r
atio in all gel-filtered fractions, FliG and FliM copy numbers, estima
ted relative to that of the hook protein from the early fractions cont
aining long, basal, flagellar fragments, were (means +/- standard erro
rs) 41 +/- 10 and 37 +/- 13 per flagellum, respectively, Extended stru
ctures were present in the earliest identifiable basal bodies, Immunoe
lectron microscopy and immunoblot gel analysis suggested that the FliG
and, to a less certain degree, the FliM contents of these structures
were the same as those for the complete basal bodies. These facts are
consistent with the postulate that FliG and FliM affect flagellar morp
hogenesis as part of the extended basal structure, formation of which
is necessary for assembly of more-distal components of the flagellum,
The determined stoichiometries will provide important constraints to m
odelling energization and switching of flagellar rotation.